1. Field of the Invention
The present invention relates to an image-forming apparatus.
2. Description of the Related Art
A conventional electrophotographic image-forming apparatus such as a printer, a facsimile machine, and a copying machine is equipped with an image-forming section. The image-forming section has a toner reservoir to which a toner cartridge is attached. The toner cartridge holds toner therein and supplies the toner into the toner reservoir. When the remaining amount of toner in the image-forming section is not sufficient or the density of printed images is not sufficient, the toner is supplied from the toner cartridge into the image-forming section.
The image-forming-section includes an agitator that is rotatably supported in the toner reservoir and agitates the toner in the toner reservoir.
With the aforementioned conventional image-forming apparatus, when the toner held in the image-forming section is agitated, the toner deteriorates gradually. It is not desirable for the image-forming section to hold a remaining amount of toner more than necessary. When the toner deteriorates, the charging characteristic of the toner becomes poor, preventing the toner from being charged sufficiently. As a result, insufficiently charged toner particles cling to the background of an electrostatic latent image formed on a photoconductive drum, leading to soiling of the surface of the photoconductive drum. This causes poor print quality.
If the image-forming section does not hold a sufficient amount of toner therein, the density of printed images becomes low or blurred (i.e., light and vague images), decreasing print quality.